Firefighter Fitness and Metabolism

February 7, 2012

What is Metabolism?

You may often here around the firehouse someone say “I have a slow metabolism.” Usually these individuals are a little on the larger size and often like to joke about their size. Unfortunately, these people are at a very high risk to keep the trend of heart related Firefighter fatalities in tact. I’m not saying that larger individuals cannot perform the job, in most cases they are great firefighters. What I am saying is that there is more to the picture than a “slow metabolism.”

There are a large number of individuals that believe the reason they are overweight has nothing to do with their appetite, and/or level of activity. They assume it is an inherent problem with their “metabolism”. So, today I wanted to clear the air around the firehouse (and other houses) about what metabolism really is.

Taber’s Medical Dictionary defines Metabolism as: The sum of all the physical and chemical changes that take place within an organism; all energy and material transformations that occur within living cells.

My definition: The bodies use of nutrients and oxygen to produce energy; measured in calories.

What is RMR or BMR?

BMR or RMR is the number of calories the body needs to maintain basic bodily function. This represents 55-60% of a person’s metabolism. The other 30-40% is the energy cost of being active and the remaining 5-10% of Metabolism is Thermo-genesis, which is the body’s response to changes in the environmental temperature.

Metabolism varies between individuals due to:

• Body Composition (Fat vs. Muscle)

• Body Weight

• Age

• Gender

Metabolism can and will change as a result of weight loss, caloric restriction, change in body composition (body fat) and exercise. When one loses weight their metabolism will typically decrease. Remember one of the variables in metabolism is weight. The engine (your body’s vital organs) must work harder for a heavier individual.

Aerobic exercise burns calories but does not have a long-standing effect on metabolism; it is temporary. Lean body mass (muscle) is metabolically more active even at rest. Please note this is not saying that aerobic activity is unnecessary in the process of weight management. In fact, research now shows that the combination of resistance training (building muscle) and aerobic exercise (burning calories) is the most effective means for losing weight.